Processing Forum

Screen name:
differenze9

differenze9's Profile

2 Posts

3 Responses

0 Followers

Activity Trend

Last 30 days

Loading Chart...

Show:

Expanded view
List view

Null pointer exception multi-classes

[1 Reply]
- 20-Nov-2012 04:30 PM
- Forum: Programming Questions
Hello, i've got a problem with my game.
I get a Null Pointer Exception.

I want the code to be clean and easy to read so the main class shall only contain the setup and draw void and a key handler. The voids used by the main class are supposed to be in another class called " voids".

So far i have only written the code supposed to draw the map (tile based).

My Main class:
1. //Using Eclipse
2. //Main class, clean version
4. import processing.core.*;
5. import java.awt.event.*;
7. public class Game2 extends PApplet implements KeyListener{
8. //Instancing classes
9. Player you = new Player();
10. maps map = new maps();
11. voids allVoids = new voids(); //the class causing errors
12. int lvl=1; //just for the development
13. public static void main(String[] args) {
14. PApplet.main(new String[] { "Game2" });
15. }
17. public void setup(){
18. size(1024,640);
19. }
21. public void draw(){
22. background(255);
23. allVoids.drawBox(); //calling the void from class "voids",
24. //supposed to be changed to a void drawing the map(background)
25. }
26. // Keypress -- works as far as i know, simply edits posX&posY from the player class
27. // to move the caracter. Outblocked to cause no errors
28. /*
29. public void keyPressed(KeyEvent e){
30. int keyCode = e.getKeyCode();
31. if (keyCode == KeyEvent.VK_RIGHT){
32. if(map.main[lvl][you.posY+1][you.posX+2]>999 || map.main[lvl][you.posY+1][you.posX+2]<900) you.posX++;
33. }
34. if (keyCode == KeyEvent.VK_LEFT){
35. if(map.main[lvl][you.posY+1][you.posX]>999 || map.main[lvl][you.posY+1][you.posX]<900) you.posX--;
36. }
37. if (keyCode == KeyEvent.VK_UP){
38. if(map.main[lvl][you.posY][you.posX+1]>999 || map.main[lvl][you.posY][you.posX+1]<900)you.posY--;
39. }
40. if (keyCode == KeyEvent.VK_DOWN){
41. if(map.main[lvl][you.posY+2][you.posX+1]>999 || map.main[lvl][you.posY+2][you.posX+1]<900)you.posY++;
42. }
43. else{
44. e.consume();
45. }
46. }*/
47. }
The maps class:
1. public class maps {
2. // simply contains an int array where every position represents a field,
3. // local variables are there to make different numbers represented equally long (square-ish shape)
4. // simply: int main[lvl][x][y]
5. int bdr=1; //outer border, hit when person leaves the field, to save space
6. //
7. // later on some of the bdr tiles are going to be changed to numbervalues like 030404
8. // so if the player walks on this tile the map is going to change to "lvl" 03 and the player will stand on
  // tile 04,04
9. //
10. int emp=901; //empty field
11. int wll=20; //wall for test
12. public int main[][][]={
13. //map 1
14. // in Eclipse the letters have the same width, therefor are all tiles represented by
15. //three letters to make the viewing easier for me
16. {
17. {bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr},
18. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
19. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
20. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
21. {bdr,emp,emp,emp,emp,wll,wll,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
22. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
23. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
24. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
25. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
26. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
27. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
28. {bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr}
29. },
30. //map 2
31. {
32. {bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr},
33. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
34. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
35. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
36. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
37. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
38. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
39. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
40. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
41. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
42. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
43. {bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr}
44. },
45. //map 3
46. {
47. {bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr},
48. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
49. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
50. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
51. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
52. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
53. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
54. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
55. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
56. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
57. {bdr,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,emp,bdr},
58. {bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr,bdr}
59. }
60. };
61. public maps(){} //constructor
62. }
And here the voids class causing problems:
import processing.core.*;

// class causing errors (i guess)

class voids extends PApplet{

//purpose, contain voids executed in the draw void to

//clean up the main class

public void drawBox(){ // void for testing

rect(5,5,50,50);

}

void drawMap(int map[][][], int lvl){

// Most necessary void: Two for-loops to get a number from the

// maps.main array and convert it to a picture (represented by

// a rectangle for testing purposes).

int m[][][]=map;

for(int a=0;a<=15;a++){

for (int b=0;b<=9;b++){

if (m[lvl][b][a]==901){

//draw empty

rect((a-1)*64,(b-1)*64,64,64);

}

if (m[lvl][b][a]==20){

//draw a wall

}

}

}

}

}

So the draw void is supposed to execute voids like allVoids.drawMap(), allVoids.drawPlayer(), allVoids.drawInventory().
But the rect() void in "voids" causes an Null Pointer Exception:

Exception in thread "Animation Thread" java.lang.NullPointerException

at processing.core.PApplet.rect(PApplet.java:11045)

at voids.drawBox(voids.java:5)

at Game2.draw(Game2.java:19)

at processing.core.PApplet.handleDraw(PApplet.java:2128)

at processing.core.PGraphicsJava2D.requestDraw(PGraphicsJava2D.java:190)

at processing.core.PApplet.run(PApplet.java:2006)

at java.lang.Thread.run(Thread.java:680)

Eclipse gives no more information than this so there are no spelling errors etc.
I could move the voids into the main class witch makes the program run, but then the main class gets so full and i want it clean ^^

Help and Comments appreciated, sorry for gramatical errors

//Differenze :)

Multi class question

[2 Replies]
- 20-Nov-2012 02:13 PM
- Forum: Programming Questions
Hello.

I am working on a simple game project and have a problem with multiple classes (static/nonstatic voids).

I want my main class to be very clean, which means only setup(), draw() and keyevent. Therefor I have a second class named voids having different voids containing rect() and image() functions. For example one for drawing a map.

So inside the main class i get:

public void setup(){
size(1024,640);

//etc

}

public void draw(){

voids.drawMap(map.main, lvl);

voids.drawPlayer(posX,posY);

}

and inside the voids class:

public void drawMap(int map[][][], int lvl){

//code drawing the map, containing:

rect(a,b,c,d);

}

this way the main class complains " Cannot make a static reference to the non-static method drawMap(int[][][], int) from the type voids" and suggests to make drawMap() static.
But if i make drawMap() static the rect() function complains " Cannot make a static reference to the non-static method rect(float, float, float, float) from the type PApplet"

Do you have any suggestions on how to fix this, I know it would work to move the drawMap void to the main class, but i want it clean.

Thanks for the help // Differenze :)

«Prev
Next »